Reciprocating ultrasound device

Abstract

A device for internal ultrasound procedures includes a motor which rotates a drive shaft and an ultrasound transducer. A gearing assembly provides reciprocating rotational motion from a unidirectional motor. A cam assembly provides reciprocating pivotal motion to the transducer. Conductors can attach to the transducer and extend through the drive shaft.

What is claimed is: 
     
       1. A medical device, comprising:
 a unidirectional rotary motor; 
 a bidirectional ultrasound transducer; and 
 a unidirectional-to-bidirectional gear assembly operatively disposed between the motor and the transducer and configured to convert unidirectional rotational motion into bidirectional rotational motion. 
 
     
     
       2. The device of  claim 1 , wherein the transducer is configured for transmitting and/or receiving ultrasound signals;
 wherein the rotary motor is operatively coupled with a first drive shaft, wherein the first drive shaft extends substantially along a rotation axis, and wherein operation of the motor rotates the drive shaft about the rotation axis; 
 wherein the gear assembly comprises an internal gear and first and second external gears, wherein the first external gear is interengaged with the second external gear, wherein the internal gear is positioned to rotate about the rotation axis, wherein the gear assembly is operatively coupled with the first drive shaft and the transducer; and 
 wherein the internal gear has a first toothed portion and a first untoothed portion and is disposed so that during rotation of the internal gear the first toothed portion alternately engages the first and second external gears. 
 
     
     
       3. The device of  claim 2 , further comprising a diametric first external gear and a diametric second external gear, wherein the diametric first external gear is positioned diametrically opposite to the first external gear and the diametric second external gear is positioned diametrically opposite to the second external gear, wherein the diametric first external gear engages both the second external gear and the diametric second external gear, and wherein the diametric second external gear engages both the first external gear and the diametric first external gear, and wherein a radially central aperture exists between the external gears and intersects the rotation axis. 
     
     
       4. The device of  claim 3 , further comprising a conduction pathway, wherein the conduction pathway extends from the transducer through the aperture. 
     
     
       5. The device of  claim 4 , further comprising a second drive shaft operatively disposed between the transducer and the gear assembly, wherein the first drive shaft includes a first lumen running therethrough and wherein the second drive shaft includes a second lumen running therethrough, wherein the first drive shaft is operatively connected with the internal gear, and wherein the conduction pathway extends from the transducer through the second and first lumens. 
     
     
       6. The device of  claim 5 , the gear assembly further comprising a third external gear and a driving gear, wherein the third external gear is disposed to rotate coaxially and in response to rotation of the second external gear, wherein the driving gear is interengaged with the third external gear and is disposed to rotate about the rotation axis, and wherein the second drive shaft is operatively connected with the driving gear. 
     
     
       7. The device of  claim 3 , wherein the internal gear further comprises a second toothed portion positioned radially opposite of the first toothed portion, wherein the first and second toothed portions have an arc length defined by the formula L=θr, where r is a radius measured from the rotation axis to toothed portion, and wherein θ≦90°. 
     
     
       8. The device of  claim 2 , further comprising a third external gear and a driving gear, wherein the third external gear is disposed to rotate coaxially and in response to rotation of the second external gear, and wherein the driving gear is interengaged with the third external gear. 
     
     
       9. The device of  claim 8 , further comprising a second drive shaft and a conduction pathway, wherein the first drive shaft is operatively connected with the internal gear, and wherein the second drive shaft is operatively connected between the driving gear and the transducer. 
     
     
       10. The device of  claim 1 , wherein the medical device is mounted in a catheter. 
     
     
       11. The device of  claim 1 , wherein the transducer rotates reciprocatingly through a range of at least 360° in each direction. 
     
     
       12. The device of  claim 2 , further comprising a frictional interface fixed relative to the internal gear, wherein the frictional interface is positioned to absorb rotational energy from the first and second external gears during rotation of the internal gear. 
     
     
       13. The device of  claim 12 , further comprising a non-toothed disc connected to one or more of the first and second external gears so that the non-toothed disc rotates in response to rotation of one or more of the first and second external gears, wherein the non-toothed disc is positioned to engage the frictional interface. 
     
     
       14. A medical device including an elongated member, comprising:
 a first motor operatively coupled with a first drive shaft extending along a length of the elongated member, wherein the first drive shaft extends substantially along a rotation axis, wherein operation of the first motor rotates the first drive shaft about the rotation axis; 
 a transducer configured for transmitting and/or receiving ultrasound signals, wherein the transducer is disposed to move about a pivot axis which is substantially perpendicular to the rotation axis; and 
 wherein the first drive shaft includes a cam surface disposed to impart pivotal motion to the transducer when the first drive shaft rotates. 
 
     
     
       15. The device of  claim 14 , further comprising an elongated slot positioned to receive the cam surface, wherein the cam surface is positioned on a part of the first drive shaft which is bent at an angular offset relative to the rotation axis. 
     
     
       16. The device of  claim 15 , further comprising a cam plate, wherein the elongated slot is situated in the cam plate, and wherein the cam plate extends from a surface of the transducer. 
     
     
       17. The device of  claim 14 , further comprising a second motor operatively coupled with a second drive shaft, wherein the second drive shaft extends substantially along the rotation axis, and wherein operation of the second motor rotates the second drive shaft about the rotation axis, wherein the transducer is operatively connected with the second drive shaft, and wherein a difference between the rotational speed of the first motor and the rotational speed of the second motor determines the speed of movement of the transducer about the pivot axis. 
     
     
       18. The device of  claim 17 , wherein the second drive shaft has a lumen extending therethrough and wherein the first and second drive shafts are positioned concentrically. 
     
     
       19. The device of  claim 14 , wherein the first motor is axially movable along the rotation axis, and wherein movement of the first motor along the rotation axis changes the range of motion of the transducer about the pivot axis. 
     
     
       20. A medical device comprising:
 a transducer configured for transmitting and/or receiving ultrasound signals; 
 a first motor operatively disposed to impart movement to the transducer about a pivot axis which is substantially perpendicular to a rotation axis; 
 a second motor operatively disposed to impart rotational motion to the transducer about the rotation axis; and 
 wherein the speed of movement of the transducer about the pivot axis is determined by a difference between the rotational speed of the first motor and the rotational speed of the second motor. 
 
     
     
       21. The device of  claim 20 , wherein the first motor is operatively coupled with a first drive shaft, wherein the first drive shaft extends substantially along the rotation axis, wherein operation of the first motor rotates the first drive shaft about the rotation axis; wherein the second motor is operatively coupled with a second drive shaft, wherein the second drive shaft extends substantially along the rotation axis, wherein operation of the second motor rotates the second drive shaft about the rotation axis; and wherein the transducer is pivotally connected to the second drive shaft. 
     
     
       22. The device of  claim 21 , wherein the second drive shaft has a lumen extending therethrough and wherein the first and second drive shafts are positioned concentrically. 
     
     
       23. The device of  claim 20 , wherein the first motor is operatively coupled with a first drive shaft, wherein the first drive shaft extends substantially along the rotation axis, wherein operation of the first motor rotates the first drive shaft about the rotation axis, wherein the first drive shaft includes a cam surface disposed to impart pivotal motion to the transducer when the first drive shaft rotates. 
     
     
       24. The device of  claim 23 , wherein the second motor is operatively coupled with a second drive shaft, wherein the second drive shaft extends substantially along the rotation axis, wherein operation of the second motor rotates the second drive shaft around the rotation axis, and wherein the transducer is pivotally connected to the second drive shaft. 
     
     
       25. The device of  claim 23 , further comprising an elongated slot positioned to receive the cam surface, wherein the cam surface is positioned on a part of the first drive shaft which is bent at an angular offset relative to the rotation axis. 
     
     
       26. The device of  claim 25 , further comprising a cam plate, wherein the elongated slot is situated in the cam plate, and wherein the cam plate extends from a surface of the transducer. 
     
     
       27. The device of  claim 26 , wherein the second motor is operatively coupled with a second drive shaft, wherein the second drive shaft extends substantially along the rotation axis, wherein operation of the second motor rotates the second drive shaft about the rotation axis; and
 wherein the transducer is pivotally connected to the second drive shaft. 
 
     
     
       28. The device of  claim 20 , wherein the first motor is movable along the rotation axis, and wherein movement of the first motor along the rotation axis changes the range of motion of the transducer about the pivot axis.